Serum and CSF from patients with amyotrophic lateral sclerosis (ALS) and neurologic controls are being studied for the presence of antibody to selected viral antigens. Antibody patterns in ALS will be compared with neurologic controls. Immunofluorescent study of ALS muscle biopsies in tissue culture is being performed. Preliminary evidence suggests that approximately ten percent of ALS patients have immunoglobulin which reacts with their fibroblasts of muscle biopsy origin in tissue culture. HL-A typing of peripheral lymphocytes from SSPE indicates that antigen W-29 may occur with increased frequency in this disorder.